In order to obtain teeth crown materials, prosthetic materials, artificial teeth and the like for dental use (hereafter, collectively referred to as dental materials), generally, curable composition and cured product thereof are used, containing an inorganic powder such as silica (silicon dioxide); a polymerizable monomer of the (meth)acrylate series; and a photopolymerization catalyst, a heat-curing catalyst or the like. Such dentistry materials are required to have esthetics, strength and durability for the substitution from natural teeth. In prior art, the use of a variety of inorganic powders has been proposed to confer a variety of capabilities to dental materials.
For example, the patent document 1 discloses a filler for dental composite in which silicon dioxide and another metal oxide are aggregated and then heat-treated at a lower temperature than the crystallization temperature of those oxides, to thereby form independent amorphous layers with silicon dioxide and the other metal oxide.
Patent document 2 describes a dental complex composition comprising a polymerizable monomer, a filler and a polymerization initiator, wherein a heat-treated aggregate of silica and another metal oxide, of which average particle size, refractive index, pore volume, BET specific surface area and primary particle size are controlled, is used as the filler.
Patent document 3 described a dental filling glass which contains SiO2, B2O3, Al2O3, P2O5, BeO, MgO, CaO, X-ray contrasting element oxide, alkaline metal oxide, and F in specific proportions, and in which Si, B and Al elements forming the glass framework are contained at specific molar ratios.